The CNC machining center technology used today has increased the production of complex components significantly. The CNC machining centers can perform 5 and 6 axis operations a very high speed. One of the most important improvements made to the technology in recent years is the automatic tool changing system. This system allows the CNC machining center to retrieve a specific tool for each operation without intervention from an operator. The advent of this technology allows one operator to setup and service several CNC machining centers, thus reducing plant operational cost.
Tool monitoring is a remedy for the unattended machining environment. Large and small facilities are continuously pursuing “lights out” production periods, reducing or eliminating the need for line operators. Error proofing is essential when considering savings opportunities with respect to labor sorting costs. One hundred percent manual (human) inspection is only 80 percent reliable, per automotive supplier quality specialists.
A major drawback with the use of automatic tool changing technology is that fact that a machine will continue to function with a defective tool. There have been several attempts to incorporate technology that will detect broken and worn tools. However the attempts have proven to be unreliable and difficult to maintain. The most popular techniques attempted include the use of laser detectors; photoelectric detectors, mechanical touch probes, and torque monitoring for spindle motors. Laser detectors, photoelectric detectors and mechanical probe fail to detect defective tools when they are chipped or cracked. Motor torque monitors usually detect only catastrophic modes of tool failures. CCD camera technology has been applied to tool setup but has been limited to off-line applications only.
The proposed invention provides an added level of security in that the measurement technique is not limited to single feature. This invention also allows the user to implement the system on all type of machine cutting tools, including drills, taps, multiple tool holders, surface cutters, and unusual shaped cutters. The invention is based on a machine vision system with compact sensors and solid state illumination capable of withstanding harsh machining center environments.